package cc.cary.vel.core.common.utils;

import javax.servlet.http.HttpServletRequest;

/**
 * @author MrBird
 */
public class IpUtils {

  private static final String UNKNOWN = "unknown";

  protected IpUtils() {

  }

  /**
   * 获取 IP地址
   * 使用 Nginx等反向代理软件， 则不能通过 request.getRemoteAddr()获取 IP地址
   * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，
   * X-Forwarded-For中第一个非 unknown的有效IP字符串，则为真实IP地址
   */
  public static String getIpAddr(HttpServletRequest request) {
    String ip = request.getHeader("x-forwarded-for");
    if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
      ip = request.getHeader("Proxy-Client-IP");
    }
    if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
      ip = request.getHeader("WL-Proxy-Client-IP");
    }
    if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
      ip = request.getRemoteAddr();
    }
    return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
  }

}
